The present invention relates to a semiconductor device and a process for producing the same, and more particularly to a technology effectively applicable to the manufacture of a semiconductor device having a tape carrier package (called the TCP).
A TCP, a TSOP (Thin Small Outline Package), a TSOJ (Thin Small Outline J-Lead Package) and a TQFP (Thin Quad Flat Package) are well known as LSI packages with which thin semiconductor devices such as IC cards are mounted. Above all, the TCP formed by mounting a semiconductor chip on a thin tape made of insulating material such as polyimide is usable for realizing an extra-thin LSI package because the thickness of resin with which the semiconductor chip in encapsulated is reducible.
A process for making such a TCP comprises the steps of placing a semiconductor chip in a device hole of an insulating tape with leads formed on one side, bonding one end portion (inner lead portion) of each lead to a bump electrode which is pre-formed on the major surface (element-forming side) of the semiconductor chip to electrically connect the lead and the semiconductor chip, encapsulating the semiconductor chip with resin by curing the potting resin applied onto the major surface of the semiconductor chip, cutting away the unnecessary portion of the insulating tape and the leads so that the other end portion (outer lead portion) of each lead can be mounted on a substrate.
Japanese Patent Laid-Open No. 57248/1991, for example, describes such a TPC.
In the aforementioned TCP, one end portion of each lead is connected via a bump electrode of Au onto the bonding pad of a semiconductor chip.
In the case of a semiconductor chip forming a logic LSI having a number of external connecting terminals (pins), bonding pads with bump electrodes to be respectively formed thereon are ordinarily disposed along the four sides of the chip. In the case of a memory LSI in which the number of pins is relatively small, however, bonding pads are disposed along one side or in the central portion of a chip. A method of concentratingly arranging the bonding pads along one side of the chip is called a one-side pad arrangement system, which is advantageous in that the chip size is reducible.
Nevertheless, there arises the following problem if a semiconductor chip employing the one-side pad arrangement system is packaged in the TCP.
When each lead is connected via the bump electrode onto the bonding pad of the semiconductor chip of the one-side pad arrangement system, the application of a potting resin onto the semiconductor chip in such a state that the semiconductor chip is supported in the device hole of an insulating tape only by the leads connected to the respective bonding pads disposed on one side thereof causes the semiconductor chip to tilt because of the weight of the resin. When the potting resin is cured, the packaging of TCP cannot be uniformized because part of the film thickness is undesirably increased.
In this case when the potting resin is applied onto the semiconductor chip in such a state that it is placed on, for example, a horizontal stage in order to prevent the semiconductor chip from being tilted (displaced) in this case, the potting resin passed through the gap between the insulating tape and the semiconductor chip tends to stick to the back of the semiconductor chip and the surface of the stage. In consequence, workability at the step of encapsulation with resin is extremely lowered.
An object of the present invention is to provide a technology of making uniform the thickness of a TCP in use in packaging a semiconductor chip of a one-side pad arrangement system.
Another object of the present invention is to provide a technology of improving the workability of assembling a TCP for use in packaging a semiconductor chip of a one-side pad arrangement system.
These and other objects and novel features of the invention may be readily ascertained by referring to the following description and appended drawings.
A brief description will be given of the representatives of the inventions disclosed in the present patent application.
(1) A semiconductor device according to the present invention comprising a tape carrier package in which a semiconductor chip is placed in the device hole of an insulating tape which is formed with a plurality of leads on the major surface of the semiconductor chip; one ends of the leads are electrically connected onto a plurality of bonding pads which are disposed in an uneven manner in a predetermined area of the major surface of the semiconductor chip; and the major surface of the semiconductor chip and one ends of the leads are at least encapsulated with resin, is characterized in that dummy bonding pads in an electrically floating state are disposed in an area different from the area where the bonding pads on the major surface of the semiconductor chip are disposed; and one ends portion of dummy leads which are formed on one side of the insulating tape are connected onto the corresponding dummy bonding pads.
(2) A semiconductor device according to the present invention in which the plurality of the bonding pads are disposed along one side of the semiconductor chip; and the bonding pads are disposed along the other opposed side of the semiconductor chip.
(3) A semiconductor device according to the present invention in which some dummy leads extending to the portion over the gap between the semiconductor chip and the insulating tape are disposed in an area along one side opposite to the one side where the bonding pads of the semiconductor chip are disposed.
(4) A semiconductor device according to the present invention in which some dummy leads extending to the portion over the gap between the semiconductor chip and the insulating tape are disposed in areas along three sides other than the other side where the bonding pads of the semiconductor chip are disposed.
(5) A semiconductor device according to the present invention in which the plurality of the bonding pads are disposed in areas along the three sides of the semiconductor chip; and the dummy bonding pads are disposed in an area along the other side of the semiconductor chip.
(6) A semiconductor device according to the present invention in which the other ends of the leads electrically connected to the bonding pads are extended outside the resin for encapsulating the semiconductor chip so that the other ends of the leads are capable of being packaged.
(7) A semiconductor device according to the present invention in which the other ends of the dummy leads are extended outside the resin for encapsulating the semiconductor chip so that the other ends of the leads are capable of being packaged.
(8) A semiconductor device according to the present invention in which the tape carrier package is mounted on a printed wiring board.
(9) A semiconductor device according to the present invention in which a plurality of the tape carrier packages are stacked on a printed wiring board.
(10) A semiconductor device according to the present invention in which a protective frame is provided around the insulating tape.
(11) A semiconductor device according to the present invention in which the semiconductor chip is encapsulated with bonding resin.
(12) A semiconductor device according to the present invention in which a flash memory is formed on the major surface of the semiconductor chip.
(13) A semiconductor device according to the present invention in which the plurality of the bonding pads are disposed in the substantially central portion of the major surface of the semiconductor chip.
(14) A semiconductor device according to the present invention in which an IC card is loaded with a printed wiring board on which the semiconductor device is mounted.
(15) A process for producing a semiconductor device of the present invention comprises the steps of:
(a) preparing an insulating tape having at least a plurality of leads including dummy leads which are formed on its major surface, and a semiconductor chip having a plurality of bonding pads which are disposed in an uneven manner in a predetermined area on its major surface and dummy bonding pads in an electrically floating state which are disposed in an area different from the area where the bonding pads are disposed;
(b) placing the semiconductor chip in the device hole of the insulating tape, electrically connecting one end portions of the leads to the corresponding bonding pads and connecting one end portions of the dummy leads to the corresponding dummy bonding pads; and
(c) at least encapsulating the major surface of the semiconductor chip and one end portions of the leads with resin.
(16) A process for producing a semiconductor device according to the present invention in which the semiconductor chip is encapsulated by curing the potting resin deposited on the major surface of the semiconductor chip.